Study On Heat Transfer Characteristics And Resistance Characteristics Of Automobile Heat Exchanger

Heat exchanger is a main part of the vehicle cooling system, which determines themaximum working efficiency of the system. The heat exchanger is studied by the meansof the empirical formulae, which is contributed to the design principle of heat exchanger.The research method usually requires a lot of time and cost to get high quality results.However, it cannot effectively make decisions or guide product design in early designperiod. The louvered fin geometry model is established base on real automobile heatexchanger, the flow field，pressure field and temperature filed distribution rule of thelouvered are analyzed. The results are showed that:Firstly, when the air flow goes into the louvered fin, the bottom air velocity ishigher. When the air flow changes the direction, the top air velocity is higher. Louveredfins heat transfer effect of aggrandizement is weaker in lower inlet velocity of air, andbegins to stabilize in high entry air velocity. But the pressure drop of louvered fins risesintensely in high entry air velocity.Secondly, the pressure drop is lowest when the louver angle at21°. It reduces7%when the louver angle increases2degrees. There is no difference in pressure dropbetween louver angle at25°and the louver angle at27°. The heat transfer coefficient oflouver angle21°is5%higher than it of louver angle25°.Thirdly, the pressure drop reduces with the louver pitch increasement. The pressuredrop louver pitch1.1mm is lower20%than its0.8mm. The pressure drop louver pitch1.4mm is also lower20%than its1.1mm. The heat transfer performance is the bestwhen the thickness o f the louver pitch is1.1mm.Fourthly, fin thickness has a great effect on the heat transfer performance of fin.The surface heat transfer coefficient increases and the pressure drop decreases by the finthickness decreasing. Therefore, the general heat transfer coefficient increases a lot. Thefin thickness of0.18mm general heat transfer coefficient is20%higher than it of0.20mm, and the fin thickness of0.16mm general heat transfer coefficient is15%higherthan that of0.18mm. The smaller louver thickness of fin, the heat transfer performanceis better.Finally, the heat exchanger structure parameters are optimized on the basis of theresults of numerical simulation. The pressure drop of updated model is decreased20%,and the heat transfer coefficient is increased4%. The results are shown that the heat transfer characteristics and resistance characteristics of the updated model are improved.